• Structural Engineering and Mechanics
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• 제72권2호
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• pp.229-244
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• 2019

Weak form integral equations are developed to investigate the flapwise bending vibration of the rotating beams. Rayleigh and Eringen nonlocal elasticity theories are used to investigate the rotatory inertia and Size-dependency effects on the flapwise bending vibration of the rotating cantilever beams, respectively. Through repetitive integrations, the governing partial differential equations are converted into weak form integral equations. The novelty of the presented approach is the approximation of the mode shape function by a power series which converts the equations into solvable one. Substitution of the power series into weak form integral equations results in a system of linear algebraic equations. The natural frequencies are determined by calculation of the non-trivial solution for resulting system of equations. Accuracy of the proposed method is verified through several numerical examples, in which the influence of the geometry properties, rotatory inertia, rotational speed, taper ratio and size-dependency are investigated on the natural frequencies of the rotating beam. Application of the weak form integral equations has made the solution simpler and shorter in the mathematical process. Presented relations can be used to obtain a close-form solution for quick calculation of the first five natural frequencies of the beams with flapwise vibration and non-local effects. The analysis results are compared with those obtained from other available published references.

• 정보처리학회논문지B
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• 제18B권4호
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• pp.193-200
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• 2011

본 논문은인간-컴퓨터 인터페이스, 가상현실의 의학 응용, 환자의 원격 모니터링과 같은 실시간 응용 분야에 적합한 인체 운동의 시각적 해석 알고리즘 (visual analyzer algorithm)을 제안한다. 본 알고리즘을 사용할 때의 비용을 줄이기 위해서, 단수의 카메라를 사용하도록 설계한다. 그리고 제안한 알고리즘을 좀 더 편리하게 사용할 수 있도록 하기 위해서 광학적 표시자의 사용을 피한다. 제안하는 알고리즘이 실시간 사용에 편리하도록 하기 위해서, 폐쇄적 형태가 되도록 설계한다. 폐쇄적 형태의 알고리즘을 설계하기 위해서, 인체의 각 관절을 기존의 3차원 관절 모델 대신 어떤 형태의 근사화도 사용하지 않고도 2차원 관절 모델로 공식화하는 아이디어를 제안한다. 그리고 이 폐쇄적 형태의 알고리즘이 높은 정확도를 갖게 하기 위해서, 계산 알고리즘을 최적화 문제로 공식화한다. 이렇게 해서 설계된 알고리즘을 인체의 각 관절에 차례대로 적용한다.

• 한국정보통신학회논문지
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• 제25권4호
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• pp.523-529
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• 2021

4차산업 혁명 시대를 맞아, 기술의 변화가 다양한 분야에 적용되고 있다. 고지서 분야에서도 자동화, 디지털화, 데이터관리가 되고 있다. 사회에서 유통되는 고지서의 형태는 수만 가지 이상이며, 이를 자동화, 디지털화, 데이터관리를 위해서는 고지서 인식이 필수적이다. 현재 다양한 고지서들을 관리하기 위해서 OCR(Optical Character Recognition) 기술을 활용한다. 이때, 정확도를 높이기 위해, 먼저 고지서 양식을 인식하면, OCR 인식 시 더 높은 인식률을 가질 수 있다. 본 논문에서는 고지서 양식을 구분하기 위해 인덱스로 사용할 수 있는 로고를 객체 인식하였으며, 이때 로고의 크기가 전체 고지서 대비 작으므로 딥러닝 기술 중 FPN(Feature Pyramid Network)을 작은 객체 검출에 활용하였다. 결과적으로, 제안하는 알고리즘을 통해서 자원 낭비를 줄이고, OCR 인식 정확도를 높일 수 있었다.

• 정보과학회 컴퓨팅의 실제 논문지
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• 제21권2호
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• pp.144-147
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• 2015

Question Answering (QA) 서비스는 사용자의 자연어 질의에 대응하는 정확한 답변을 제공하는 시스템이다. 본 연구는 특정 도메인에 관련한 사용자들의 질문에 대해 QA 서비스가 자동으로 대응하는 방법에 관한 연구이다. 이를 수행하기 위하여 사용자의 자연어 질문을 이해하고, 정형 데이터 및 비정형 데이터로부터 사용자 질문에 적합한 답변을 도출하여 제공하는 방법을 제시한다. 실험 결과 top 1 accuracy 68%, top 5 accuracy 77% 결과를 얻었다. 또한 본 논문은 QA 시스템 내부 모듈이 전체 accuracy에 미치는 영향에 대해서도 기술하였다.

• 대한한의학회지
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• 제34권1호
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• pp.103-115
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• 2013

Objectives: This study proposes a new form of English translation in comparison with that shown in English books related to Sasang Constitutional medicine formulae which have been published up to now. Methods: This study formulated a new form of English translation guidelines by making a comparative analysis of the English translation cases listed in "Korean-English Dictionary of Oriental Medicine", "Longevity and Life Preservation in Eastern Medicine", and "Introduction to Sasang Constitutional Medicine". Results: This study as a common rules suggested that names of preparation form should be placed at the very end of the formula name and the first letters of the major words of the formula name should be capitalized. In addition, for the sake of accuracy in English translation of the formula name, this study divided the formula names into 8 types. The 8 sorts of types include: (a) Materia Medica + Preparation Form, (b) Materia Medica + Indication + Preparation Form, (c) Materia Medica Numbers + Preparation Form, (d) Indication + Preparation Form, (e) Concept + Preparation Form, (f) Concept + Materia Medica + Preparation Form, (g) Concept + Indication + Preparation Form, (h) Etcetera. In these types, medicinal herbs should be written in scientific name, and translation of indication can follow Noun+~ing participle form. In case of the terms having a Korean-medicine-based meaning, this study aimed for source-oriented translation. Conclusions: This study provides a general English translation method and examples of the formula names for Sasang constitutional medicine.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1998년도 춘계학술대회논문집; 용평리조트 타워콘도, 21-22 May 1998
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• pp.302-307
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• 1998

In the production of semiconductor wafer, optical and electron microscopes, ion-beam, laser device must maintain their alignments within a sub-micrometer. This equipment requires a vibration free environment to provide its proper function. Especially, lithography and inspection devices, which have sub-nanometer class high accuracy and resolution, have come to necessity for producing more improved giga and tera class semiconductor wafers. This high technology equipments require very strict environmental vibration standard, vibration criteria, in proportion to the accuracy of the manufacturing, inspecting devices. The vibration criteria of high sensitive equipment should be represented in the form of exactness and accuracy, because this is used as basic data for the design of building structure and structural dynamics of equipment. The study on the evaluation of the factors affecting the permissible vibration criteria is required to design the efficient isolation system of the semiconductor manufacturing of equipment. This paper deals with the properties of the effected factor for vibration criteria of high sensitive equipment.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.483-486
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• 2001

Rapid Prototyping(RP) has been widely applied in designing and developing processes a new product. The functional requirements of a rapid prototyping system are high speed and high accuracy, and they depend on the operating parameters, some of which can be set by users. The accuracy is evaluated by dimensional errors and form errors of manufactured pars. A specially designed specimen with various features has been used for the accuracy evaluation. According to the Taguchi experimental design techniques, and orthogonal array of experiments has been set which has the least number of experimental runs to find the parametric effects. A laser scanner is used to obtain the point data of the parts and Surfacer is used to determine the lengths and angles. The conditions for the FDM manufacturing parametrs have been found.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.838-841
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• 2000

To improve the accuracy of products and improve the product quality, we need to enhance the machining accuracy of the machine tools. To this point of view, measurement and inspection of finished part as well as error analysis of machine tools has been studied for last several decades. OMM(On the Machine Measurement) has been issued to alternate with CMM, pointing out disadvantages of high expenses and lots of setting time in CMM. In this paper, we study 1) the spherical surface manufacturing by volumetric error compensation of machine tool, 2) the system development of OMM without detaching work piece from a bed of machine tool after working. 3) the generation of the finished part profile by On the machine measurement. Furthermore, the output of OMM is compared with that of CMM, and verified the feasibility of the measurement system.

• 제어로봇시스템학회논문지
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• 제4권4호
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• pp.420-426
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• 1998

It is the purpose of this paper to make a preliminary study on the use of repetitive control to improve velocity accuracy by eliminating repetitive disturbances caused by machining inaccuracies of the axis of rotation location. If the control system can be intelligent enough to compensate for such machining errors, then one may be able to improve the accuracy of the velocity control, or alternatively, one may maintain the same accuracy and relax the machining tolerances required. This could decrease cost significantly. Experiments are performed testing repetitive control methods on a constant speed rolling operation testbed. The experimental results show very substantial decreases in the tracking error of the system. Spectral data of the output motion are given to demonstrate the attenuation of the disturbance frequencies and harmonics, related to the bandwidth being used. It is seen that the simplest form of repetitive control which is very easily implemented, can produce striking improvement in control system performance in such belt drive rolling operations, and the learning can be accomplished in a short time.

• 소성∙가공
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• 제8권3호
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• pp.284-293
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• 1999

The rigid-plastic finite element analysis requires a large amount of computation time due to its non-linearity. For economic computation, mismatching refinement, and efficient domain decomposition method with different mesh density for each sub domain, is developed. A modified velocity alternating scheme for the interface treatment is proposed in order to obtain good convergence and accuracy. As a numerical example, the axisymmetric extrusion process is analyzed. The results are discussed for the various velocity update schemes form the viewpoint of convergence and accuracy. The three-dimen-sional extrusion process with rectangular section is analyzed in order to verify the effectiveness of the proposed method. Comparing the results with those of the conventional method of full region analysis, the accuracy and the computational efficiency of the proposed method are then discussed.